Grade-meter.



J. K. STEWART.

\ GRADE METER.

APPLICATION FILED JAN. 27, 191's.

Patented Jan. 6

To all whom it mag/concern UNITED STATES PATENT OFFICE.

enn e sanwanr, or CHICAGO, ILLINOIS, ASSIGNOR T STEWART-WARNER sPEEnomnrrER CORPORATION, or CHICAGO, ILLINOIS, A CORPORATION or VIRGINIA.

'gBe it known that 1, JOHN K. STEWART,

' ajcitiaenof the United States, residingat Chifcagodin the county of Cook andState of Illinois, have invented new and usful Improvements in Grade-Meters, of which the following is a specification, reference being had to the accompanying drawings, forming a part thereof. I

The purpose of this invention is to provide an improved form of grade meter par- 3 ticulai'ly designed with a view to rendering the. indicating means substantially dead beat in operation and. not subject to influences or forces other than change of inclination It consists of the features and elements'described and-shown in the drawings'as indicated by the claims.

In the drawings :Figure l is a face View of-an instrument embodying this invention.

Fig. 2 is an interior detail view partly in section showing the mechanism which is responsive to change of grade and'the indicating means connected thereto. Fig. 3 is a top plan view of the parts shown in Fig. 2.- 'Fig. dis a detail section taken as indicatedfat lined- 4 on Fig. 3. Fig. 5 is a detail section taken as indicated atline 5-5 on Fig.4; 'Fig. 6' is a section taken as indi l pinion, B is mounted loosely upon the spin- Particularly cated at line O-6 on Fig. 4::

The grade meter which is the sub ect of this invention comprises essentially a pen I dulum, A, operatively connected with a segmental gear, A and an indicating dial wheel, B, whose peripheral scale, B is' arrangedto appear at the window, C of the casing, C, and which is actuated through a pinion, -B meshing withv the segmental gear, A Obviously, if the scale, B is cor rectly proportioned, its position with respect to a fixed line such as the index, (J on the faceof-the casing will indicate the inch-- nation of the vehicle on which the instrument is mounted with respect to the constantly vertical position of the pendulum, A. However, on account of the weight of the pendulum, A, the rapid acceleration or retardation'of the veliicle in starting or stopping quickly is likely to overcome. the ,in-

' ertia of the pendulum and thus to move the scale of the grade meter even on level.

ground, rendering its indications more or less uncertain and unreliable. To prevent this effect. as far as possible, the pendulum,

.- GRADE-METER.

Patented Jan. 6, 1914.

Application filed January 27, 1913. Serial No. 744,342. r

sudden starting or stopping of the vehicle will tend merely to swing the part, A

about the pivot, A by which it is connected to the stirru p member, A and will not affect'the position of the shaft, A to which said stirrup is secured and which also carries rigidly the gear segment, A for operating the dial wheel, B; Vhenthe 'inclis nation of the vehicle is actually changed, however, the constant pull of gravity upon the jointed pendulum, A, will tend to straighten out its joint and thus rotate the shaft, A through the proper angle for indicating the actual, grade. As a further precaution, however, the pinion, B may be connected withthe dial wheel, B, through a yielding spring connection as. indicated in Figs. 2 and 8', which show a spiral spring, D, similar to the hair spring of a watch, and

having one end connected to a flange, B of .the pinion, B and the. other end secured to the hub B of'the dial wheel, B, said hub serving to connect the dial wheel rigidly with thespindle, B. It will be understood of course that with this arrangement the dle, B, ofthe dial wheel, 13. when this spring connection is employed between the'pinio-n, B and the-dial wheel, B,

the latter being thus yieldingly connected to the pendulum, A, is somewhat likely to be carried past the true reading by a rather sudden change'of grade of the vehicle, so

that even though the pendulum itself isv practically dead beat the scale. still may not be, and may vibrate to either side of the correct scale .reading before coming to rest there-at, in the manner of a sensitive gal- ,vanometer' or other delicate measuring-instrument. This tendency, however, may be overcome to some extent by placing the hollow shell, which constitutes the wheel, B, with two or more steel'balls, E, whose friction against each other and against the inner wall of the shellyB, will tend to reduce the excess motion of the shell and cause the wheel, B, to come to rest very nearly at the correct scale reading. In addition tothis, if desired, a pendulum, F, may be hung loosely upon the spindle, B", so that its our- 2 nal friction thereon will assist 'imthe retarding of the wheel, B.

Fig. 4, indicates how the balls, E, are pre- Vented from interfering-with the action of the pendulum, F, namely, by the insertion of a partition flange, B, in the shell. Analyz ing theaction of the pendulum, F, it will be seen that if a sudden shock or acceleration experienced by the yehiele should cause the stirrup portion, A of the pendulum, A, to swing about its fulcrum axis and thus actuate the gear segment, A and the dial wheel, B, through the'pinion,"B. the rot'a-. tion' of'the dial wheel, B, thus causedwould be in the opposite direction of that of the pendulum, A, by virtue. of the, gearing between said elements, while theswing of the pendulum, F, would be in the same direction fasthat of the pendulum, A, and would thus directly tend to frictionally'. counteract the latter; If the two pendulums, A and F, be

made of exactly equal efiective lengths so as to have equalperiods ofovibration, it is' obvious that they will continue'to counteract eachother a-s long as they yibrat'c. But,

- since the, primary purpose'of each; of. the

pendulums, A and F, and particularly of.

-.the pendulum, A, is not thatef ayibrating pendulum but that ofaplumb bob merely,

the tendency to pendulous vibration may be reduced in one or both oitthem by providing a chamber as at, A, (see Fig. 6-), and furnishing said chamber with a small'steel ball, A", whose 'induced'moti'on within. the chammovement of the pendulum and will thus tend "to damp. its swing her will notb-in harmony with the periodic and bring it to rest more promptly.

-1-. I'n'agrade meter comprising a pendur bration of the'pendulum. g I

. 2. In a grade meter comprising apendu- 111m, an indicating member and means op (pendulum;

a rotatably mounted indicating member and a driving pinion therefor meshing with the I gear of the pendulum, said indicating member having a shaft to which 1t.1s rigidly secured; a second pendulum journaled upon said shaft for frictionally neutralizing excessive vibration of the first pendulum.

" 4. In a grade meter comprising a pendulum, an indicating member, means whereby the member is operatiyely connected with the pendulum, said pendulum having a CIT chamber and a1ball loosely 'fitted in the I chamber for damping the vibration of the 5.; In a grade meter comprising a pendulum, an indicating member consisting of a hollow dial. wheel. and memos. operatively,

connecting them, including a yielding and elasticconnection for absorbing vibration of the pendulum; a plurality of balls loosely carried in said hollow wheel for fricti'onally damping the rotation oi said wheel.

' 6. In a'grade meter comprising a pendulum, an indicating member consisting of a connectihgthem,including a yielding and to which .it is rigidly secured; a second pendulum journaled upon saidshaft for 'friction'ally damping the rotation of said -wheel.

.- In testimony whe-reof,jI have hereunto set my hand, at chicago, Illinois, this'30th day of September, 1912'.

I JOHN K. STEWART."

Witnesses: 1

C. B. SMITH, STANHOPE HUnsoN.

hollow dial wheel and means operatiijely elastic connection for absorbing vibration I of the pendulum, said wheel having a shatt 

